1. Field of the Invention
This invention relates to an electroforming process and more particularly to an an electroforming process for producing high resolution, multi-relief, shell metal nameplates having a plastic filled reverse.
2. Description of the Prior Art
Numerous processes and methods of forming three-dimensional metallic designs, letters or nameplates are known and used in the art. Typically, such processes comprise the creation of a master image which may be by machining, or by various etching methods. From the master image, a production tool comprising a reverse, or negative, of the master, is formed by either a plating or casting process. This negative is then used in a plating operation whereby a metal, typically nickel or copper, is plated onto the negative. The plated material, when removed, forms the embossed nameplate or sign. Such processes are disclosed in U.S. Pat. Nos. 497,303 issued to Callow, 924,020 issued to Walter and 172,563 issued to Libberton. Other U.S. Patents which describe related methods include U.S. Pat. Nos. 2,874,085 issued to Brietzke, 3,574,074 issued to Eccles and 4,462,873 issued to Watanabe. The latter relates primarily to a method for arranging a plurality of separately electroformed letters to form a name and not to the method of producing the letters themselves.
A problem with prior art processes is that the known methods of creating a master image tend to lack sufficient detail for certain applications. Further, these processes generally do not provide for multi-relief capability, i.e., only one plane of detail is possible. Because such electroformed nameplates or designs are three-dimensional, a further problem occurs with strength and durability of nameplates fabricated with the techniques of the prior art. A nameplate fabricated of a very thin metal, for example, between five to fifteen thousandths of an inch, is not sufficiently rigid. Manufacturers may put an adhesive backing sheet behind the nameplate in an effort to add rigidity but such backings typically are of a compressible material and incompletely fill the cavity formed in the reverse of the nameplate by plating process. These backings also cannot fill the additional cavity caused by the raised lettering on the front of the plate. Alternatively, nameplates of the prior art may be formed of thicker metal, for example, between twenty to thirty thousandths of an inch or more. Such nameplates are rigid but are more costly as they require more metal and longer plating times, and are much heavier.
Accordingly, it is the object of the present invention to provide a method for the production of nameplates having a high degree of detail.
It is a further object of the present invention to provide a method for the production of multi-relief nameplates.
It is another object of the present invention to provide a method for the production of nameplates which does not require costly unique tooling.
It is another object of the present invention to provide a method for the production of nameplates which are rigid, strong, and light in weight.
It is a further object of the present invention to provide a method for the production of nameplates which are less expensive to manufacture.
It is another object of the present invention to provide a method for the production of nameplates which can be made in sheets and separated into individual nameplates by horizontal cutting rather than vertical punching, thus eliminating further exposed surfaces subsequent to cutting.
It is another object of the present invention to provide a method for the production of nameplates which does not result in misregistration during the cutting process.
Briefly, a preferred embodiment of the method of the present invention includes creating a master image by photoexposing and chemically etching a photopolymer. A production tool is made up and comprises the reverse of the master image repeated in rows and columns to form a sheet. This tool is plated with a metal such as nickel or copper to a thickness of between five to ten thousandths of an inch, and backfilled with a mixture of powdered nylon and an epoxy resin, to form a smooth, solid backing. The front surface of the sheet is chrome-plated and painted as desired. The sheet is separated into individual nameplates by a material removal means, e.g. a fly-cutting mill or a sander which horizontally severs the nameplates at their adjacent raised edges. The individual nameplates may then be provided with an adhesive backing or studs for mounting.
It is an advantage of the present invention that nameplates may be produced with a great degree of detail.
It is a further advantage of method of the present invention that multi-relief nameplates may be produced.
It is another advantage of the present invention that the nameplates are lightweight yet rigid and strong.
It is another advantage of the present invention that the nameplates are less costly to manufacture relative to their weight and durability.
It is another advantage of the present invention that costly unique tooling is eliminated and that high resolution nameplates can be produced more economically than with present methods.
It is another advantage of the present invention that individual nameplates are separated by horizontal cutting, thus eliminating misregistration and exposure of newly cut edges.
These and other objects and advantages of the present invention will no doubt become obvious to those of ordinary skill in the art after having read the following detailed description which is illustrated in the various drawing figures.